Assessment of the US diet in national nutrition surveys: national collaborative efforts and NHANES.

The National Nutrition Monitoring and Related Research Program includes conducting national surveys to estimate the dietary intake and nutritional status of the US population. As part of this program, a 10-y comprehensive plan has been developed to strengthen nutrition-monitoring efforts in the United States. Emphasis is placed on improving coordination and comparability among data collection methods across federal agencies and on conducting relevant research. Current collaborative efforts between the US Departments of Health and Human Services (DHHS) and Agriculture (USDA) include coordinating the national food-consumption surveys in the areas of planning population coverage, by using comparable dietary intake methods, and targeting research toward improving dietary methods. The National Health and Nutrition Examination Survey (NHANES) contributes population data on diet, nutritional status, and health outcomes to the Nutrition Monitoring Program. The third NHANES (1988-1994) includes 40,000 noninstitutionalized people aged > or = 2 mo and oversamples blacks, Mexican Americans, children, and elderly people and uses an automated 24-h recall as the primary dietary instrument. Assessing dietary intake in heterogeneous populations in national surveys poses many methodologic, statistical, and interpretive issues and highlights the need for specific research to improve dietary assessment methods.